I am interested in all opinions on cut in rpms for secondaries on a holley 650 dp carby model is 4777-4..When vehicle is stationary in park, and air cleaner is off,i can rev it to over 5000 rpm without secondaries cutting in..I know the vehicle is not under load as in driving onroad ,When engine is switched off, the secondaries do open up, but only at the last second, after the primaries are fully open..I have seen on some forums that some blokes shorten the dogleg link between the primary and secondary throttle shafts to make the secondary cut in when the primary is 2/3 open..I have size 64 jets primary and 70 in secondary,351 clevo seems lacking in power,it has std 2v heads, stage 3 hyd cam,110psi double valve springs,extractors/roller rockers,max compression is 190 psi mim is 160 psi. Carby earlier had size 70 and 73 jets and was blowing excessive black smoke a lot---thanks for any replies-Ned----ned351